A silicon-containing group (hereinafter, refereed to as a reactive silicon group), which has a hydrolyzable group bonded to the silicon atom and which is crosslinkable by forming a siloxane bond, is a well-known functional group represented, for example, by --Si(OCH.sub.3).sub.3.
This functional group is a group which is hydrolyzed by moisture in air and form --Si(OH).sub.3 and the like, that produces a siloxane bond (Si--O--Si) by silanol condensation reaction with other reactive silicon groups. ##STR1##
Accordingly, the polymer containing the reactive silicon group can be cross-linked and cured in the presence of moisture at ambient temperature. Among such polymers, a polymer the main chain of which is a rubber-like polymer is a viscous liquid at room temperature, and is characterized by becoming a rubbery elastic materials upon curing and is widely used as a sealing material in a construction industry and other industries. The sealing material is used in order to maintain watertight or airtight of construction materials such as wall materials by filling up gaps (seams) thereof with the sealing material and curing it.
Among such rubber-like polymer, a saturated hydrocarbon polymer such as polyisobutylene is a polymer which can form a cured product excellent in weather resistance, heat resistance and gas barrier character. There is a problem, however, that it takes a long time for one week or more until the inside of the sealing material can be cured though the curing at the surface can be proceeded smoothly when the sealing material is cured by moisture in air because the moisture barrier character is also large due to the large gas barrier character. On this account, a compound excellent in curability of a deep part, which can be smoothly cured to the inside at normal temperature by dispersing a hydrated metal salt in the compound, is proposed (Japanese Kokai Publication Hei-2-185565).
By the way, it occurs quite often that a polymer containing reactive silicon groups is used as a compound to which a silanol condensation catalyst as a curing catalyst, filler, plasticizer and the like are added. A curable compound can be roughly classified into a one-part curable compound and a two-part curable compound.
The one-part curable compound is convenient because it is a liquid-like substance comprising one component which is mixed with all additives as described above and it does not needs to be mixed at the time of use, but it must be stored in a completely dried state not to be cured before use. The two-part curable compound is inconvenient because it is need to be mixed at the time of use, but it is not needed to be dehydrated completely like the one-part one because the polymer having the reactive silicon groups is hard to be cured in the presence of some moisture and in the absence of the silanol condensation catalyst.
When the above-mentioned hydrated metal salt or water is used as a source of water to cure the polymer, the one-part curable compound can not be applied. This is because curing reaction starts immediately after the polymer, the silanol condensation catalyst and water are mixed together.
A titanium compound or a tin compound is also often used as the silanol condensation catalyst, and many of these compounds are decomposed by moisture. Thus it is expected that these silanol condensation catalyst is also decomposed by the hydrated metal salt. Accordingly, when the hydrated metal salt is used as a source of water, it must be added to a curable compound just before use (curing) or be added to a main ingredient containing the polymer in case of the above-mentioned two-part compound.
It is inconvenient, however, that only the hydrated metal salt is mixed just before use. In case where it is combined with the main ingredient, there is a problem that a viscosity of the main ingredient increases due to proceeding slightly in curing of the polymer containing the reactive silicon groups.
Furthermore, a silane-coupling agent is often used jointly in sealing material as an adhesion promoter. There is a problem, however, that the silane-coupling agent cannot be combined with both the main ingredient and the curing agent even if it is necessary to be used as an additive because it is easily reacted with water. For example, when a silane-coupling agent such as .gamma.-isocyanatepropyltrimethoxysilane, ONCCH.sub.2 CH.sub.2 CH.sub.2 Si(OCH.sub.3).sub.3, is added to the main ingredient, it reacts with the hydrated metal salt, and when it is added to the curing agent, it is decomposed by the silanol condensation catalyst. Thus it loses a role of imparting adhesiveness as a silane-coupling agent.